Plugging device for extrusion container

ABSTRACT

A DEVICE FOR PLUGGING EXTRUSION CONTAINERS AND COMPRISING A DIE, A CYLINDRICAL DIE CAVITY CONTAINING THE BILLET TO BE EXTRUDED AND AN EXTRUSION RAM ASSOCIATED WITH A SLIDABLE PLUGGING BLOCK WHICH IS ADAPTED TO CLOSE OFF THE REAR END OF THE EXTRUSION CONTAINER AS CONSIDERED IN THE DIRECTION OF EXTRUSION. THE RELATIVE MOTION OF THE RAM ROD AND THE PLUGGING BLOCK CAUSES THE LUBRICANT TO BE INJECTED INTO THE EXTRUSION CONTAINER UNDER VERY HIGH PRESSURE, THE LUBRICANT BEING MAINTAINED PREFERABLY IN THE PLASTIC STATE AND AT A SUITABLE TEMPERATURE INSIDE AN ANNULAR FEED RESERVOIR WHICH IS FORMED BETWEEN THE RAM ROD AND THE PLUGGING BLOCK. ESSENTIALLY, SAID ANNULAR RESERVOIR COMMUNICATES THROUGH THE PLUGGING BLOCK WITH A COMPRESSION CHAMBER WHICH IS FILLED WITH LUBRICANT AND INTO WHICH THE ROD OF A PISTON IS ADAPTED TO PENETRATE IN LEAK-TIGHT MANNER, SAID PISTON BEING IN TURN INTENDED TO CARRY OUT A MOVEMENT OF DISPLACEMENT WITHIN A SEPARATE CYLINDER UNDER THE ACTION OF AN AUXILIARY DRIVING FLUID.

March 2, 1971 c. sAuvE PLUGGING DEVICE FOR mx'rnusrou com'uman Filed Feb. 10, 1969 United States Patent "ice 3,566,641 PLUGGING DEVICE FOR EXTRUSION CONTAINER Charles Sauve, 9 Bis Avenue Jean Jaures, Versailles, Yvelines, France Filed Feb. 10, 1969, Ser. No. 798,001 Claims priority, application France, Feb. 22, 1968, 140,940 Int. Cl. 1321b 45/02 US. C]. 7243 4 Claims ABSTRACT OF THE DISCLOSURE A device for plugging extrusion containers and comprising a die, a cylindrical die cavity containing the billet to be extruded and an extrusion ram associated with a slidable plugging block which is adapted to close off the rear end of the extrusion container as considered in the direction of extrusion. The relative motion of the ram rod and the plugging block causes the lubricant to be injected into the extrusion container under very high pressure, the lubricant being maintained preferably in the plastic state and at a suitable temperature inside an annular feed reservoir which is formed between the ram rod and the plugging block. Essentially, said annular reservoir communicates through the plugging block with a compression chamber which is filled with lubricant and into which the rod of a piston is adapted to penetrate in leak-tight manner, said piston being in turn intended to carry out a movement of displacement within a separate cylinder under the action of an auxiliary driving fluid.

The present invention relates to a plugging device for the rear portion which is located opposite to the die of an extrusion container and through which the extrusion ram is adapted to penetrate.

There has already been described in US. Pat. No. 3,3 80,270, a plugging system comprising a die, a cylindrical die cavity containing the body to be extruded and an extrusion ram associated with a slidable plugging lock which is adapted to close off the rear end of said extrusion container relative to the direction of extrusion, wherein the relative motion of the ram rod and the plugging block produces an injection of lubricant under very high pressure into the interior of the extrusion container, said lubricant being maintained especially in the plastic state and at a suitable temperature inside an annular feed reservoir formed between the ram rod on the one hand and the plugging block on the other hand.

Preferably, the rear portion of the ram rod which has a larger diametrical cross-section serves to force the lubricant out of its reservoir towards the interior of the extrusion container after the plugging block has been applied against said container, the quantity of lubricant injected being exactly that which is necessary for the purpose of filling under the desired extrusion conditions the space which is left free between the internal wall of said container and the body to be extruded.

Under these conditions, the ram rod moves with respect to the plugging block over a distance equal to the travel required for the extrusion of the body within the interior of the extrusion container.

In this system, the volume of lubricant injected is constant and corresponds to the volume swept within the annular feed reservoir by the movement of the ram. With this quantity of lubricant which is thus known and according to the method of extrusion adopted, it is possible to carry out either a conventional extrusion operation or extrusion with complete expulsion of the body to be extruded or alternatively an extrusion in which the pressure 3,566,641 Patented Mar. 2, 1971 of lubricant is maintained during the course of the extrusion operation at a variable value which is in fact slightly lower than the extrusion pressure whilst the ram bears continuously on the rear face of said body throughout the extrusion operation.

The present invention is directed to an improvement made in the arrangements which are covered by Pat. No. 3,380,270 whereby the volume of lubricant injected into the extrusion container and/or the pressure of said lubricant within the feed reservoir can be varied at will, said variations in volume or in pressure being either continuous or noncontinuous as required, depending on the method of extrusion to be carried out.

With this objective, the improvement under consideration consists primarily in establishing a communication through the plugging block between said annular reservoir and a compression chamber which is filled with lubricant and into which the rod of a piston is adapted to penetrate in leak-tight manner, said piston being in turn intended to carry out a movement of displacement within a separate cylinder under the action of an auxiliary driving fluid.

The compression chamber which is directly connected to the annular feed reservoir is thus provided as a function of the position of the piston rod with a variable volume in which the pressure of lubricant can also be continuously adjusted, especially with respect to the pressure of said lubricant within the interior of the extrusion container.

As an advantageous feature and according to another property of the invention, the piston is subjected within the separate cylinder to a differential pressure of the auxiliary driving fluid which is exerted on both faces of said piston. Moreover, the pressure of the lubricant within the annular reservoir can be brought to a value which is higher than or equal to the pressure within the die cavity of the extrusion container. Finally, and in accordance with an alternative embodiment which can also be contemplated, the pressure of lubricant can be continuously variable and determined by a programmer which produces action on the differential pressure of the auxiliary fluid on the piston and which controls the position of said piston within the interior of the separate cylinder.

The different properties mentioned above and considered either separately or if necessary in combination will become more readily apparent from the description of one example of construction which follows below, it being clearly understood that this example is given solely by way of indication and not in any sense by way of limitation. Reference is made to the single figure of the accompanying drawings in which a plugging system for an extrusion container in accordance with the present invention is shown in axial cross-section.

There is shown in this figure the leader 1 of an extrusion press which holds in position by means of a support member 2 a die-holder 3 for a die 4, said die being placed at the end of the cylindrical die cavity 5 of an extrusion container 6. The preliminary and temporary closure of the die 4 at the front end of this latter is carried out by means of a removable seal plug 7 whilst the other end of the die cavity is adapted to cooperate with a plugging block 8, the corresponding extrimity of which is adapted to fit within a conical flare 9 formed in the end of the die cavity 5. The rod 10 of a ram 11 is mounted within said plugging block 8 and is extended by a portion 12 having a diametrical cross-section which is larger than that of the central portion of the rod so as to form around this latter an annular recess or reservoir 13 which is normally filled with a suitable lubricating material. There is also shown in the figure the body 15 or billet which is to be extruded within the container and which is supported by a cradle 16.

In accordance with the present invention, the annular reservoir 13 is connected through the thickness of the plugging block 8 by way of a duct 17 to a compression chamber 18 which is supplied with lubricant through an isolating valve 19 from an admission pipe 20. The rod 21 of a piston 22 is intended to penetrate into said compression chamber 18. Said piston is fitted in the outer surface thereof with sealing rings 23 and is mounted within the interior of an auxiliary cylinder 24 which is defined by a casing 25. Said casing is closed at the upper end by a flange 26 which is applied against a counter-flange 27 formed at the corresponding end of the plugging block 8, these two components being assembled by means of screws 28. Within the interior of the cylinder 24, the piston 22 defines two spaces having variable volumes which can be put separately into communication via two pipes 29 and 30 respectively with a source (not shown) of an auxiliary fluid which modifies the position of the piston 22 within said cylinder and consequently controls the extent of penetration of the rod 21 into the compression chamber 18. Seals such as the seal 31 ensure leaktightness between the cylinder 24 which contains the auxiliary fluid and the chamber 18 which is filled with lubricant and which communicates with the annular reservoir 13 via the duct 17.

The operation of the plugging system for an extrusion container as illustrated in the drawings is generally similar in principle to the system described in the patent which was cited earlier. However, by virtue of the improvement which is contemplated herein and which essentially consists in providing a communication between the annular reservoir 13 and the variable-volume compression chamber 18, it is apparent that lubricant can be injected into the die cavity of the extrusion chamber in accordance with a predetermined law while extrusion is in progress.

Thus, by varying the position of the rod 21 of the piston 22 within the compression chamber 18, a correlative variation can be produced in the volume of lubricant injected. Furthermore, by producing action on the respective differential pressures of the auxiliary fluid which are applied to the faces of the piston 22, action can also be produced on the instantaneous pressure of the lubricant which can be continuously higher than the pressure required for the extrusion of the billet 15: in this contingency, the pressure of the lubricant within the die cavity 5 is hydrostatic and permits of complete expulsion of the billet. In another variant, the pressure of the lubricant is adjusted in such a manner as to be at the most equal to that which is required for the extrusion of the billet.

Finally, in another mode of utilization, action can be produced on the pressure of the auxiliary fluid which is admitted through the pipes 29 and 30 on each side of the faces of the piston 22 so that these respective pressures follow a program as established by a computer (not shown in the drawings), taking into account the particular parameters which are related to a given extrusion opera- 4 tion as a function, for example, of the travel of the ram within the cylindrical die cavity.

As will be readily understood, the present invention is not limited in any respect to the exemplified embodiment which has been more particularly contemplated in the foregoing but extends to all alternative forms.

What is claimed is:

1. A device for plugging an extrusion container, comprising a die, a cylindrical die cavity containing the body to be extruded and an extrusion ram associated with a slidable plugging block which is adapted to close off the rear end of said extrusion container relative to the direc T tion of extrusion, wherein the relative motion of the ram rod and the plugging block produces an injection of lubricant under very high pressure into the interior of the extrusion container, said lubricant being maintained especially in the plastic state and at a suitable temperature inside an annular feed reservoir formed between the ram rod on the one hand and the plugging block on the other hand, and wherein said annular reservoir communicates through the plugging block with a compression chamber which is filled with lubricant and into which the rod of a piston is adapted to penetrate in leak-tight manner, said the annular reservoir is brought to a value which is either higher than or equal to the pressure within the die cavity of the extrusion container.

4. A device for plugging an extrusion container as defined in claim 1, wherein the pressure of lubricant is continuously variable and determined by a programmer which produces action on the differential pressure of the auxiliary fluid on the piston and which controls the position of said piston within the separate cylinder.

References Cited UNITED STATES PATENTS 3,380,270 4/1968 Sauve 72272 3,455,134 7/1969 Thompson 72-271 3,072,251 1/1963 Sauve 72-42 3,364,717 1/1968 Green 72-272 3,367,163 2/1968 Zeitlin et al 7227l CHARLES W. LANHAM, Primary Examiner M. J. KEENAN, Assistant Examiner U.S. Cl. X.R. 72-45, 271, 272 

